Filter dashpages to show only available ones

src/Aspire.Dashboard/Components/Pages/Metrics.razor

@@ -59,12 +59,17 @@
                                 <ChildContent>
                                     @if (PageViewModel.Dashpages.Length is not 0)
                                     {
-                                        <FluentTreeItem Text="@Loc[Aspire.Dashboard.Resources.Metrics.DashpagesSectionName]" title="@Loc[Aspire.Dashboard.Resources.Metrics.DashpagesSectionName]" InitiallyExpanded="true">
-                                            @foreach (DashpageDefinition dashpage in PageViewModel.Dashpages)
-                                            {
-                                                <FluentTreeItem @key="dashpage" Class="nested" Text="@dashpage.Name" Data="@dashpage" title="@dashpage.Name" InitiallySelected="@(dashpage.Name == PageViewModel.SelectedDashpage?.Name)"/>
-                                            }
-                                        </FluentTreeItem>
+                                        var filteredDashpages = PageViewModel.Dashpages.Where(PageViewModel.IsDashpageAvailable).ToList();
+
+                                        if (filteredDashpages.Count is not 0)
+                                        {
+                                            <FluentTreeItem Text="@Loc[Aspire.Dashboard.Resources.Metrics.DashpagesSectionName]" title="@Loc[Aspire.Dashboard.Resources.Metrics.DashpagesSectionName]" InitiallyExpanded="true">
+                                                @foreach (DashpageDefinition dashpage in filteredDashpages)
+                                                {
+                                                    <FluentTreeItem @key="dashpage" Class="nested" Text="@dashpage.Name" Data="@dashpage" title="@dashpage.Name" InitiallySelected="@(dashpage.Name == PageViewModel.SelectedDashpage?.Name)"/>
+                                                }
+                                            </FluentTreeItem>
+                                        }
                                     }
                                     @foreach ((var meter, var instruments) in PageViewModel.Instruments.GroupBy(i => i.Parent).OrderBy(g => g.Key.MeterName))
                                     {

src/Aspire.Dashboard/Components/Pages/Metrics.razor.cs

@@ -153,6 +153,9 @@ private void UpdateApplications()
         _applications = TelemetryRepository.GetApplications();
         _applicationViewModels = ApplicationsSelectHelpers.CreateApplications(_applications);
         _applicationViewModels.Insert(0, _selectApplication);
+
+        PageViewModel.ApplicationNames = _applications.Select(a => a.ApplicationName).ToImmutableHashSet(StringComparers.OtlpApplicationName);
+
         UpdateSubscription();
     }
 
@@ -226,6 +229,69 @@ public sealed class MetricsViewModel
         public required MetricViewKind? SelectedViewKind { get; set; }
 
         public required ImmutableArray<DashpageDefinition> Dashpages { get; init; }
+
+        public ImmutableHashSet<string> ApplicationNames { get; set; } = [];
+
+        internal bool IsDashpageAvailable(DashpageDefinition dashpage)
+        {
+            if (dashpage.Charts.Count == 0)
+            {
+                return false;
+            }
+
+            bool foundOne = false;
+            bool allExplicitResources = true;
+
+            foreach (var chart in dashpage.Charts)
+            {
+                bool isInstrumentAvailable = IsInstrumentAvailable(chart.InstrumentName);
+
+                if (isInstrumentAvailable)
+                {
+                    foundOne = true;
+                }
+                else if (chart.IsRequired)
+                {
+                    // A required chart's instrument isn't available.
+                    return false;
+                }
+
+                if (chart.ResourceName is not null)
+                {
+                    if (IsResourceAvailable(chart.ResourceName))
+                    {
+                        foundOne = true;
+                    }
+                    else
+                    {
+                        // A chart's explicit resource isn't available.
+                        return false;
+                    }
+                }
+                else
+                {
+                    allExplicitResources = false;
+                }
+            }
+
+            if (!allExplicitResources && SelectedApplication.Id is null)
+            {
+                // No resource is selected and at least one chart doesn't specify an explicit resource.
+                return false;
+            }
+
+            return foundOne;
+
+            bool IsInstrumentAvailable(string instrumentName)
+            {
+                return Instruments?.Any(i => string.Equals(i.Name, instrumentName, StringComparisons.OtlpInstrumentName)) ?? false;
+            }
+
+            bool IsResourceAvailable(string resourceName)
+            {
+                return ApplicationNames.Contains(resourceName);
+            }
+        }
     }
 
     [JsonConverter(typeof(JsonStringEnumConverter))]
@@ -318,5 +384,4 @@ public void Dispose()
         _applicationsSubscription?.Dispose();
         _metricsSubscription?.Dispose();
     }
-
 }

src/Shared/StringComparers.cs

@@ -16,6 +16,8 @@ internal static class StringComparers
     public static StringComparer UrlPath => StringComparer.OrdinalIgnoreCase;
     public static StringComparer UrlHost => StringComparer.OrdinalIgnoreCase;
     public static StringComparer Attribute => StringComparer.Ordinal;
+    public static StringComparer OtlpInstrumentName => StringComparer.OrdinalIgnoreCase;
+    public static StringComparer OtlpApplicationName => StringComparer.OrdinalIgnoreCase;
 }
 
 internal static class StringComparisons
@@ -31,4 +33,7 @@ internal static class StringComparisons
     public static StringComparison EnvironmentVariableName => StringComparison.InvariantCultureIgnoreCase;
     public static StringComparison UrlPath => StringComparison.OrdinalIgnoreCase;
     public static StringComparison UrlHost => StringComparison.OrdinalIgnoreCase;
+    public static StringComparison Attribute => StringComparison.Ordinal;
+    public static StringComparison OtlpInstrumentName => StringComparison.OrdinalIgnoreCase;
+    public static StringComparison OtlpApplicationName => StringComparison.OrdinalIgnoreCase;
 }

tests/Aspire.Dashboard.Components.Tests/Pages/MetricsViewModelTests.cs

@@ -0,0 +1,44 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using Aspire.Dashboard.Model;
+using Aspire.Dashboard.Otlp.Model;
+using Xunit;
+using static Aspire.Dashboard.Components.Pages.Metrics;
+
+namespace Aspire.Dashboard.Components.Tests.Pages;
+
+public sealed class MetricsViewModelTests
+{
+    [Fact]
+    public void IsDashpageAvailable()
+    {
+        OtlpInstrument instrument = new()
+        {
+            Name = "present-instrument",
+            Description = "",
+            Options = null!,
+            Parent = null!,
+            Type = OtlpInstrumentType.Histogram,
+            Unit = null!
+        };
+
+        MetricsViewModel vm = new()
+        {
+            Dashpages = [],
+            SelectedDuration = null!,
+            SelectedViewKind = MetricViewKind.Graph,
+            SelectedApplication = new() { Id = ResourceTypeDetails.CreateSingleton("my-instance", "my-replica-set"), Name = "" },
+            Instruments = [instrument],
+            ApplicationNames = ["present-application"],
+        };
+
+        Assert.True(vm.IsDashpageAvailable(new() { Name = "", Charts = [new() { InstrumentName = "present-instrument", Title = "" }] }));
+        Assert.True(vm.IsDashpageAvailable(new() { Name = "", Charts = [new() { InstrumentName = "present-instrument", Title = "", ResourceName = "present-application" }] }));
+        Assert.False(vm.IsDashpageAvailable(new() { Name = "", Charts = [new() { InstrumentName = "present-instrument", Title = "", ResourceName = "absent-application" }] }));
+        Assert.True(vm.IsDashpageAvailable(new() { Name = "", Charts = [new() { InstrumentName = "present-instrument", Title = "" }, new() { InstrumentName = "absent-instrument", Title = "" }] }));
+        Assert.False(vm.IsDashpageAvailable(new() { Name = "", Charts = [new() { InstrumentName = "absent-instrument", Title = "" }] }));
+        Assert.False(vm.IsDashpageAvailable(new() { Name = "", Charts = [new() { InstrumentName = "absent-instrument", Title = "" }, new() { InstrumentName = "absent-instrument", Title = "" }] }));
+        Assert.False(vm.IsDashpageAvailable(new() { Name = "", Charts = [new() { InstrumentName = "present-instrument", Title = "" }, new() { InstrumentName = "absent-instrument", Title = "", IsRequired = true }] }));
+    }
+}